Enzyme Activity Variability and Comparison in Soils under Medicinal versus Crop Plants of Anguo City, China

Long-term continuous cultivation of different plant species in a similar agroecosystem intensively may result in divergent variability in soil fertility, particularly soil biochemical properties. In this study, an investigation was conducted to clarify the variability of five soil enzyme activities (urease, protease, catalase, polyphenol oxidase and alkaline phosphatase) of croplands under medicinal plants (herbal fields) and food crops (crop fields) in Anguo city, a traditional cultivation base for Chinese medicinal plants in China. The results showed that five soil enzyme activities were similar between herbal and crop fields. However, soil urease and alkaline phosphatase activities of herbal and crop fields decreased significantly with soil depth (0-60 cm), while protease, catalase, polyphenol oxidase activities were similar in all soil layers for two kinds of fields. There were largely variation scenes at linear correlation analysis between soil physicochemical traits and enzymatic activities under medicinal plant versus crop fileds although extensively significant correlations were presented. In conclusion, soil enzyme activities were similar in two type of farmlands, and soil urease and alkaline phosphatase activities decreased with soil depth for both fields. Inconsistent linear correlations between soil physicochemical traits and enzymatic activities under medicinal plant versus crop fields were presented, so soil enzymatic activity variation was subjected to soil physicochemical traits dominated by agronomic managements designed for specific plant species

Effects of day-night supplemental UV-A on growth, photosynthetic pigments and antioxidant system of pea seedlings in glasshouse

A glasshouse experiment was carried out to investigate the effects of day-night supplemental UV-A on growth, photosynthetic pigments and antioxidant system (contents of antioxidant substances and antioxidant enzyme activity) of pea seedlings substrate-cultivated in glasshouse. The results show that supplemental UV-A did not significantly affect shoot and root to shoot ratio of pea seedlings, but root and total biomass were modified.  Day supplemental UV-A slightly increased root and total biomass of pea seedlings, while night supplemental UV-A significantly decreased the root and total biomass. Supplemental UV-A did not affect the contents of  shoot chlorophyll a and carotenoid of pea seedlings. Nevertheless, day supplemental UV-A significantly  decreased chlorophyll b content in shoot of pea seedlings, while night supplemental UV-A slightly decreased  shoot chlorophyll b content. In addition, supplemental UV-A did not significantly affect the contents of shoot  vitamin C, phenolic compounds and flavonoid of pea seedlings. However, day supplemental 6 h and night  supplemental 3 h slightly decreased shoot anthocyanin content of pea seedlings, while night supplemental 6 h significantly reduced shoot anthocyanin content. Finally, supplemental UV-A did not significantly affect shoot peroxidase activity and catalase activity.Key words: UV-A, photosynthetic pigment, antioxidant enzymatic activity, antioxidant substance, pea seedlin

Bubble dynamics in a compressible viscous liquid

Microbubble dynamics are associated with cavitation damage to pumps, turbines and propellers, as well as applications in biomedical ultrasonics, sonochemistry and cavitation cleaning. The compressible effects of liquid are essential, which are associated with acoustic radiation at the inception of a bubble and the end of collapse. Viscous effects are important for microbubbles. This thesis is concerned with microbubble dynamics in a viscous compressible liquid near a rigid boundary. The compressible effects are modelled by using the weakly compressible theory. The viscous effects are approximated using the viscous potential flow theory, because the flow field is characterised as being an irrotational flow in the bulk volume but with a thin viscous boundary layer at the bubble surface. Consequently, the phenomenon is modelled by using the boundary integral method. The numerical results are shown in good agreement with the Keller-Miksis equation, experiments and computations based on the Navier-Stokes equations. Numerical studies were carried out for microbubble dynamics near a rigid boundary as well as subject to an acoustic wave. The bubble oscillation, topological transform, jet development and penetration through the bubble and the energy of the bubble system are simulated and analysed regarding the compressible and viscous effects

Cleaning effects due to shape oscillation of bubbles over a rigid boundary

Recent experiments have revealed the interesting cleaning effects that take place due to the shape mode oscillation of bubbles over a rigid boundary. While a microbubble was undertaking shape oscillation moving over a bacterial biofilm, it removed the contaminants from the boundary and created a clean path through the biofilm. This demonstrated much higher cleaning efficiency than that associated with the volume oscillation of cavitation bubbles; however, the mechanism is unknown. Here, we study this phenomenon using the boundary integral method with the viscous effects modeled using the viscous potential flow theory and the compressible effects using the weakly compressible theory. The viscous stress at the rigid boundary is approximated using the boundary layer theory. We observed that the natural frequencies of shape mode oscillation decrease significantly due to the presence of the boundary. The shear stress at the boundary due to the shape oscillation of a nearby bubble is at least 20 times higher than that due to volume oscillation with the same energy and is significant only within the area directly beneath the bubble. This is explained by the notably faster decay for higher shape modes of the kinetic energy in the fluid as the distance to the center of the bubble r increases with the induced velocity of mode k decaying at a rate of O(r-(k+ 2)) away from the bubble. These results achieve excellent agreement with the intriguing cleaning effects first observed in the experiment and explain the mechanism behind this new highly efficient method of cleaning

Crowdsourcing Cybersecurity: Cyber Attack Detection using Social Media

Social media is often viewed as a sensor into various societal events such as disease outbreaks, protests, and elections. We describe the use of social media as a crowdsourced sensor to gain insight into ongoing cyber-attacks. Our approach detects a broad range of cyber-attacks (e.g., distributed denial of service (DDOS) attacks, data breaches, and account hijacking) in an unsupervised manner using just a limited fixed set of seed event triggers. A new query expansion strategy based on convolutional kernels and dependency parses helps model reporting structure and aids in identifying key event characteristics. Through a large-scale analysis over Twitter, we demonstrate that our approach consistently identifies and encodes events, outperforming existing methods.Comment: 13 single column pages, 5 figures, submitted to KDD 201

Pointer Temperature and Humidity Meter Detection Based on Machine Vision

A new method is proposed to achieve the accurate segmentation and reading of different types of pointer temperature and humidity instruments. The Canny edge detection operator is applied to detect edges of the meter gray image, and the scale line distribution arc and scale lines is obtained according to distribution characteristics of the scale line. The pointer is fitted by concentric method within the radius of the arc. OCR identifies the scale value of the dial, and then determines the corresponding reading number of each scale line and dividing value by mapping relation. Three different types of meters are used to detect, and experiments results demonstrate that the proposed method can achieve accurate segmentation of pointer and scales, as well as accurately calculate the readings of instrument

Pointer Temperature and Humidity Meter Detection Based on Machine Vision

A new method is proposed to achieve the accurate segmentation and reading of different types of pointer temperature and humidity instruments. The Canny edge detection operator is applied to detect edges of the meter gray image, and the scale line distribution arc and scale lines is obtained according to distribution characteristics of the scale line. The pointer is fitted by concentric method within the radius of the arc. OCR identifies the scale value of the dial, and then determines the corresponding reading number of each scale line and dividing value by mapping relation. Three different types of meters are used to detect, and experiments results demonstrate that the proposed method can achieve accurate segmentation of pointer and scales, as well as accurately calculate the readings of instrument